January and into February is without a doubt the best time to install new pine straw and mulch.  Heat and humidity greatly increases the rate at which your mulch degrades and breaks down. By installing during the winter your mulch will look great longer giving you by far the most bang for your buck.  Additionally, with all the leaves cleaned up your existing mulch is all but gone leaving your plants unprotected in the cold freezing temperatures.  Adding new mulch will give your plants the added blanket of protection.  Plus, new mulch will make your outdoor space look great